The MSU Extension Service offers these tips for protecting your plants.
First of all, and most importantly, cover your plants. Fruits and flowers are the least tolerant when it comes to freezing temperatures and so are container plants.
If possible, place your plants inside a protective structure such as your house, garage, greenhouse, or shed or place a protective cover over them.
Windbreaks, such as fences, buildings and temporary coverings also help protect plants from the cold.
It’s also a good idea to water your plants and the soil they are rooted in before and during a freeze so that water is available to the plant’s roots.